Bowl tenon size guide

[Dan Masshardt]

I recently got the Glenn Lucas bowl turning DVD. Good DVD by the way.

One is the things Glenn uses when turning bowls is something he made to go on his live center to indicate the size he wants his tenons to be.

Slide the tailstock up with no blank and reference against the jaws where you want the tenon to be. Or use two indicators to mark the range for your jaws.

I liked the idea so I asked Rick to make me a collar for my live center. A bolt and a couple nuts and a cut out indicator and it's ready to go.

I'm pleased with it. The only think I'd do different right now if I were to get another one is have it made thinner as it's too wide to be effective in marking tenons with the standard jaws. Since I planned to use it with bigger jaws anyway, it's all good.

 

[Fish30114]

Pretty cool Dan, sometimes the simplest things can really be a big help!

 

[The Penguin]

tip for marking tenons for standard jaws...

this works with the Oneway live center or the Powermatic clone

bring the live center up to the wood.
Lay a #2 pencil on top of the live center
slide pencil over to wood to mark tenon

that's it.

the resulting circle is almost perfectly sized for standard (#2) jaws.

 

[Dan Masshardt]

tip for marking tenons for standard jaws... this works with the Oneway live center or the Powermatic clone bring the live center up to the wood. Lay a #2 pencil on top of the live center slide pencil over to wood to mark tenon that's it. the resulting circle is almost perfectly sized for standard (#2) jaws.

That is a good tip for those jaws. Thanks.

 

[Bill in Buena Park]

Dan, do you think something like the old-style circle cutting tool could be used - like shown in the pictures below? I think this could be mounted in the drill chuck and used to mark - maybe even start a cut - for a tenon. The cutters are HSS, I believe. And they are adjustable down to the smaller chuck jaw size.

 

[Charlie_W]

Dan, do you think something like the old-style circle cutting tool could be used - like shown in the pictures below? I think this could be mounted in the drill chuck and used to mark - maybe even start a cut - for a tenon. The cutters are HSS, I believe. And they are adjustable down to the smaller chuck jaw size.

Good thinking!
I would only use this for reference and mark with a pencil.
I fear that introducing this fly cutter to the spin wood blank would result in the cutter/drill Chuck rotating. Could create a hazard and also. Rotating the morse taper in the tail stock quill could gall the mating surfaces.

 

[Dan Masshardt]

I think someone uses something like that.

There are all kinds of ways to size a tenon. What I like about my idea is that it's out of the way and doesn't require a change in tooling. Changing out from live center to drill chuck and put the cutter in. Too much in the way too. Not for me.

I'll report back on how mine works after awhile.

 

[walshjp17]

Dan, do you think something like the old-style circle cutting tool could be used - like shown in the pictures below? I think this could be mounted in the drill chuck and used to mark - maybe even start a cut - for a tenon. The cutters are HSS, I believe. And they are adjustable down to the smaller chuck jaw size.

Good thinking!
I would only use this for reference and mark with a pencil.
I fear that introducing this fly cutter to the spin wood blank would result in the cutter/drill Chuck rotating. Could create a hazard and also. Rotating the morse taper in the tail stock quill could gall the mating surfaces.

I like the circle cutter idea but agree there could be a hazard if it rotates under power. How about moving the cutter up to the wood so it is touching and then rotate the wood in the head stock by hand so that a faint circle is evident. If the size is wrong, adjust the cutter accordingly, rinse and repeat until the size is right. Remove the cutter and then cut the tenon your regular way.

 

[bobleibo]

These are both great ideas and tools. I just use a skew and calipers for my tenons but can sure see some advantages to these for a lot more than just tenons. You have my mind going a million miles an hour for ideas to help me with a few things.
Thanks for starting this thread Dan.

 

[SteveG]

Hey Bob...be very careful. You do not want to fall of your brain when it is going that fast: you could get hurt!!

 

[KBs Pensnmore]

I use several bits of 1/8" flat steel bar, that are made with points to suit the radius of the chuck, one mark is the center and the other the minimum for the distance required, laid on the tool rest with the centre located, it marks the diam required as the chuck rotates.
I used to use dividers, but kept grabbing the wrong ones, usually ending up undersized, after several stuff ups, I came up with this idea.
Kryn

 

[Dan Masshardt]

I use several bits of 1/8" flat steel bar, that are made with points to suit the radius of the chuck, one mark is the center and the other the minimum for the distance required, laid on the tool rest with the centre located, it marks the diam required as the chuck rotates. I used to use dividers, but kept grabbing the wrong ones, usually ending up undersized, after several stuff ups, I came up with this idea. Kryn

Having a tenon too big or two small for your chuck is a terrible thing thing. Happened to me a couple times.

That's why I must own every size set of jaws. And chucks to hold them. ;-)

 

[Charlie_W]

I use several bits of 1/8" flat steel bar, that are made with points to suit the radius of the chuck, one mark is the center and the other the minimum for the distance required, laid on the tool rest with the centre located, it marks the diam required as the chuck rotates. I used to use dividers, but kept grabbing the wrong ones, usually ending up undersized, after several stuff ups, I came up with this idea. Kryn

Having a tenon too big or two small for your chuck is a terrible thing thing. Happened to me a couple times.

That's why I must own every size set of jaws. And chucks to hold them. ;-)

Yup!
You don't need a 14" bowl rolling off the lathe onto the floor because a #2 tenon just plain snapped off the bottom of the bowl (green wood).
There just was not enough wood there to hold it.
I also have gone to all dovetail jaws instead of serrated.